Oral Care Compositions and Methods of Use

ABSTRACT

This invention relates to oral care compositions comprising arginine, zinc citrate and zinc oxide, and an orally acceptable carrier, as well as to methods of using and of making these compositions.

FIELD

This invention relates to oral care compositions comprising arginine orsalt thereof, zinc oxide and zinc citrate, and an orally acceptablecarrier, as well as to methods of using and of making thesecompositions.

BACKGROUND

Natural buffering capacity of human saliva is controlled principally bythe carbonic acid/bicarbonate system. Upon acid exposure from anexternal source (soft drinks, fruit juices, coffee) or internal source(stomach acid), this chemical system aids in neutralizing saliva towardhigher pH values, which protects enamel. Poor saliva buffering capacitycan cause poor oral health including increased risk for enamel erosion,caries, and high levels of oral bacteria. Arginine and other basic aminoacids have been proposed for use in oral care and are believed to havesignificant benefits in combating cavity formation and toothsensitivity. Commercially available arginine-based toothpaste containsarginine bicarbonate and precipitated calcium carbonate, but notfluoride. The carbonate ion is believed to have cariostatic properties,and the calcium is believed to form in complex with arginine to providea protective effect.

However, the formulation of certain oral care compositions presentsspecial challenges. For example, not all preservatives are active athigher pH. Some preservatives negatively affect the taste or aestheticsof the product. While certain preservatives, such as ethanol orparabens, are known to be effective at a range of pHs, thesepreservatives are not suitable for all products or all markets.

Zinc formulations also present challenges. Zinc is a well-knownantimicrobial agent used in toothpaste compositions. Zinc is also awell-known essential mineral for human health, and has been reported tohelp strengthen dental enamel and to promote cell repair. Unfortunately,conventional toothpaste formulations often require a high concentrationsof zinc, e.g., 2% by weight or more, to achieve efficacy. At thisconcentration, the zinc imparts a notably astringent taste to thecomposition.

Accordingly, there is a need for improved oral care compositions thatpromote rapid and/or sustained buffering capacity of saliva.

BRIEF SUMMARY

It has been found that the combination of a basic amino acid (i.e.,arginine) and one or more sources of zinc (i.e., zinc oxide and zinccitrate, e.g., zinc citrate trihydrate) provides surprisingly effectivebuffering effects to counteract acidic conditions in the oral cavity.

Therefore, in one aspect, disclosed is an oral care composition(Composition 1.0) comprising:

-   -   a. Basic amino acid in free or salt form, wherein the basic        amino acid is arginine (e.g., free form arginine);    -   b. zinc oxide and zinc citrate; and    -   c. an orally acceptable carrier.        For example, the invention contemplates any of the following        compositions (unless otherwise indicated, values are given as        percentage of the overall weight of the composition)    -   1.1 Composition 1, wherein the composition maintains a pH over        5.0 (e.g., about 5.2) when challenged in an acidic aqueous        solution with a cola beverage in an amount of about 90% v/v        (e.g., about 91%) based on the total volume of the solution.    -   1.2 Composition 1 or 1.1, wherein the composition maintains a pH        over 3.9 (e.g., about 3.92 or 4.0) when challenged in an acidic        aqueous solution with a cola beverage in an amount of about 90%        v/v (e.g., about 91%) based on the total volume of the solution.    -   1.3 Any of the preceding compositions, wherein the composition        maintains a pH over 3.0 (e.g., about 3.3) when challenged in an        acidic aqueous solution with a cola beverage in an amount of        about 90% v/v (e.g., about 91%) based on the total volume of the        solution.    -   1.4 Any of the preceding compositions, wherein the composition        maintains a pH over 5.5 (e.g., about 5.5, 5.6 or 5.7) when        challenged in an acidic aqueous solution with a cola beverage in        an amount of about 80% v/v (e.g., about 83%) based on the total        volume of the solution.    -   1.5 Any of the preceding compositions, wherein the composition        maintains a pH over 4.0 (e.g., about 4.2, 4.3, 4.4 or 4.5) when        challenged in an acidic aqueous solution with orange juice in an        amount of about 55% v/v (e.g., about 55.5%) based on the total        volume of the solution.    -   1.6 Any of the preceding compositions, wherein the composition        maintains a pH over 6.0 (e.g., about 6.1) when challenged in an        acidic aqueous solution with orange juice in an amount of about        33% v/v (e.g., about 33.3%) based on the total volume of the        solution.    -   1.7 Any of the preceding compositions, wherein the composition        maintains a pH over 5.0 (e.g., about 5.1 or 5.6) when challenged        in an acidic aqueous solution with orange juice in an amount of        about 33% v/v (e.g., about 33.3%) based on the total volume of        the solution.    -   1.8 Any of the preceding compositions, wherein the composition        maintains a pH over 7.0 (e.g., about 7.1, 7.2, 7.3, 7.4, 7.5,        7.6, 7.7, 7.8 or 7.9) when challenged in an acidic aqueous        solution with 0.01M HCl in an amount of about 60% v/v based on        the total volume of the solution.    -   1.9 Any of the preceding compositions, wherein the composition        maintains a pH over 8.0 (e.g., about 8.1, 8.2, 8.3, 8.4, 8.5,        8.6, 8.7, 8.8 or 8.9) when challenged in an acidic aqueous        solution with 0.01M HCl in an amount of about 60% v/v based on        the total volume of the solution.    -   1.10 Any of the preceding compositions, wherein the composition        maintains a pH over 7.0 (e.g., about 7.1, 7.2, 7.3, 7.4, 7.5,        7.6, 7.7, 7.8 or 7.9) 6 hours after sucrose challenge.    -   1.11 Any of the preceding compositions, wherein the composition        maintains a pH over 8.0 (e.g., about 8.1, 8.2, 8.3, 8.4, 8.5,        8.6, 8.7, 8.8 or 8.9) 6 hours after sucrose challenge.    -   1.12 Any of the preceding compositions, wherein the composition        maintains a pH over 9.0 (e.g., about 9.1, 9.2, 9.3, 9.4, 9.5,        9.6, 9.7, 9.8 or 9.9) 6 hours after sucrose challenge.    -   1.13 Any of the preceding compositions, wherein the composition        maintains a pH over 7.0 (e.g., about 7.1, 7.2, 7.3, 7.4, 7.5,        7.6, 7.7, 7.8 or 7.9) 24 hours after sucrose challenge.    -   1.14 Any of the preceding compositions, wherein the composition        maintains a pH over 8.0 (e.g., about 8.1, 8.2, 8.3, 8.4, 8.5,        8.6, 8.7, 8.8 or 8.9) 24 hours after sucrose challenge.    -   1.15 Any of the preceding compositions, wherein the composition        maintains a pH over 9.0 (e.g., about 9.1, 9.2, 9.3, 9.4, 9.5,        9.6, 9.7, 9.8 or 9.9) 24 hours after sucrose challenge.    -   1.16 Composition 1.0 wherein the basic amino acid has the        L-configuration (e.g., L-arginine).    -   1.17 Any of the preceding compositions wherein the arginine is        in free form.    -   1.18 Any of the preceding compositions wherein the basic amino        acid is provided in the form of a di- or tri-peptide comprising        arginine, or salts thereof.    -   1.19 Any of the preceding compositions wherein the arginine is        present in an amount corresponding to 1% to 15%, e.g., 3 wt. %        to 10 wt. % of the total composition weight, about e.g., 1.5%,        4%, 5%, or 8%, wherein the weight of the basic amino acid is        calculated as free form.    -   1.20 Any of the preceding compositions wherein the arginine is        present in an amount from 0.1 wt. %-6.0 wt. %. (e.g., about 1.5        wt %).    -   1.21 Any of the preceding compositions wherein the arginine is        present in an amount of about 1.5 wt. %.    -   1.22 Any of the preceding compositions wherein the amino acid is        L-arginine.    -   1.23 Any of the preceding compositions wherein the amino acid is        free form arginine.    -   1.24 Any of the preceding compositions wherein the amino acid is        arginine phosphate.    -   1.25 Any of the preceding compositions wherein the amino acid is        arginine hydrochloride.    -   1.26 Any of the preceding compositions wherein the amino acid is        arginine bicarbonate.    -   1.27 Any of the preceding compositions wherein the amino acid is        arginine ionized by neutralization with an acid or a salt of an        acid.    -   1.28 Any of preceding compositions wherein the composition is        ethanol-free.    -   1.29 Any of the preceding compositions further comprising a        fluoride source selected from: stannous fluoride, sodium        fluoride, potassium fluoride, sodium monofluorophosphate, sodium        fluorosilicate, ammonium fluorosilicate, amine fluoride (e.g.,        N′-octadecyltrimethylendiamine-N,N,N′-tris(2-ethanol)-dihydrofluoride),        ammonium fluoride, titanium fluoride, hexafluorosulfate, and        combinations thereof    -   1.30 Any of the preceding compositions wherein the fluoride        source is sodium fluoride.    -   1.31 Any of the preceding compositions wherein the fluoride        source is a fluoride salt present in an amount of 0.1 wt. % to 2        wt. % (0.1 wt %-0.6 wt. %) of the total composition weight        (e.g., sodium fluoride (e.g., about 0.32 wt. %).    -   1.32 Any of the preceding compositions wherein the fluoride        source is a soluble fluoride salt which provides fluoride ion in        an amount of from 50 to 25,000 ppm (e.g., 750-2000 ppm, e.g.,        1000-1500 ppm, e.g., about 1000 ppm, e.g., about 1450 ppm)    -   1.33 Any of the preceding compositions wherein the fluoride        source is sodium fluoride which provides fluoride in an amount        from 750-2000 ppm (e.g., about 1450 ppm)    -   1.34 Any of the preceding compositions wherein the fluoride        source is sodium fluoride and which provides fluoride in an        amount from 1000 ppm-1500 ppm.    -   1.35 Any of the preceding compositions wherein the fluoride        source is sodium fluoride and which provides fluoride in an        amount of about 1450 ppm.    -   1.36 Any of the preceding compositions wherein the pH is between        7.5 and 10.5, e.g., 8-9.5, e.g., 7.2-9.0, about 8.0, about 9.0.    -   1.37 Any of the preceding compositions further comprising        calcium carbonate and/or precipitated calcium carbonate.    -   1.38 Any of the preceding compositions further comprising an        effective amount of one or more alkali phosphate salts, e.g.,        sodium, potassium or calcium salts, e.g., selected from alkali        dibasic phosphate and alkali pyrophosphate salts, e.g., alkali        phosphate salts selected from sodium phosphate dibasic,        potassium phosphate dibasic, dicalcium phosphate dihydrate,        calcium pyrophosphate, tetrasodium pyrophosphate, tetrapotassium        pyrophosphate, sodium tripolyphosphate, disodium        hydrogenorthophoshpate, monosodium phosphate, pentapotassium        triphosphate and mixtures of any of two or more of these, e.g.,        in an amount of 0.1-20%, e.g., 0.1-8%, e.g., e.g., 0.2 to 5%,        e.g., 0.3 to 2%, e.g., 0.3 to 1%, e.g about 0.5%, about 1%,        about 2%, about 5%, about 6%, by weight of the composition.    -   1.39 Any of the preceding compositions comprising tetrapotassium        pyrophosphate, disodium hydrogenorthophoshpate, monosodium        phosphate, and pentapotassium triphosphate.    -   1.40 Any of the preceding compositions comprising a        polyphosphate.    -   1.41 The composition of 1.40, wherein the polyphosphate is        tetrasodium pyrophosphate.    -   1.42 The composition of 1.42, wherein the tetrasodium        pyrophosphate is from 0.1-1.0 wt % (e.g., about 0.5 wt %).    -   1.43 Any of the preceding compositions further comprising an        abrasive or particulate (e.g., silica).    -   1.44 Any of the preceding compositions wherein the silica is        synthetic amorphous silica (e.g., 1%-28% by wt.) (e.g., 8%-25%        by wt.).    -   1.45 Any of the preceding composition wherein the silica        abrasives are silica gels or precipitated amorphous silicas,        e.g. silicas having an average particle size ranging from 2.5        microns to 12 microns.    -   1.46 Any of the preceding compositions further comprising a        small particle silica having a median particle size (d50) of 1-5        microns (e.g., 3-4 microns) (e.g., about 5 wt. % Sorbosil AC43        from PQ Corporation, Warrington, United Kingdom).    -   1.47 Any of the preceding compositions wherein 20-30 wt % of the        total silica in the composition is small particle silica (e.g.,        having a median particle size (d50) of 3-4 microns) and wherein        the small particle silica is about 5 wt. % of the oral care        composition.    -   1.48 Any of the preceding compositions comprising silica wherein        the silica is used as a thickening agent, e.g., particle silica.    -   1.49 Any of the preceding compositions further comprising a        nonionic surfactant, wherein the nonionic surfactant is in an        amount of from 0.5-5%, e.g, 1-2%, selected from poloxamers        (e.g., poloxamer 407), polysorbates (e.g., polysorbate 20),        polyoxyl hydrogenated castor oil (e.g., polyoxyl 40 hydrogenated        castor oil), and mixtures thereof.    -   1.50 Composition 1.50, wherein the poloxamer nonionic surfactant        has a polyoxypropylene molecular mass of from 3000 to 5000 g/mol        and a polyoxyethylene content of from 60 to 80 mol %, e.g., the        poloxamer nonionic surfactant comprises poloxamer 407.    -   1.51 Any of the preceding compositions, wherein the ratio of the        amount of zinc oxide (e.g., wt. %) to zinc citrate (e.g., wt %)        is from 1.5:1 to 4.5:1 (e.g., 2:1, 2.5:1, 3:1, 3.5:1, or 4:1).    -   1.52 Any of the preceding compositions, wherein the zinc citrate        is in an amount of from 0.25 to 1.0 wt % (e.g., 0.5 wt. %) and        zinc oxide may be present in an amount of from 0.75 to 1.25 wt %        (e.g., 1.0 wt. %) based on the weight of the oral care        composition.    -   1.53 Any of the preceding compositions wherein the zinc citrate        is about 0.5 wt %.    -   1.54 Any of the preceding compositions wherein the zinc oxide is        about 1.0 wt %.    -   1.55 Any of the preceding compositions where the zinc citrate is        about 0.5 wt % and the zinc oxide is about 1.0 wt %.    -   1.56 Any of the preceding compositions wherein the benzyl        alcohol is present from 0.1-0.6 wt %, (e.g., 0.1-0.4 wt %) e.g.        about 0.1 wt. %, about 0.2 wt. %, or about 0.3 wt. %.    -   1.57 Any of the preceding compositions wherein the benzyl        alcohol is about 0.1 wt %.    -   1.58 Any of the preceding composition wherein benzyl alcohol is        present at is considered a preservative.    -   1.59 Any of the preceding compositions comprising polymer films.    -   1.60 Any of the preceding compositions comprising flavoring,        fragrance and/or coloring agent.    -   1.61 The composition of 1.61, wherein the flavoring agent is        sodium saccharin, sucralose, or a mixture thereof    -   1.62 Any of the preceding compositions, wherein the composition        comprises a thickening agent selected from the group consisting        of carboxyvinyl polymers, carrageenan, xanthan, hydroxyethyl        cellulose and water soluble salts of cellulose ethers (e.g.,        sodium carboxymethyl cellulose and sodium carboxymethyl        hydroxyethyl cellulose).    -   1.63 Any of the preceding compositions, wherein the composition        comprises sodium carboxymethyl cellulose (e.g., from 0.5 wt.        %-1.5 wt. %).    -   1.64 Any of the preceding compositions comprising from 5%-40%,        e.g., 10%-35%, e.g., about 15%, 25%, 30%, and 35% water.    -   1.65 Any of the preceding compositions comprising an additional        antibacterial agent selected from halogenated diphenyl ether        (e.g. triclosan), herbal extracts and essential oils (e.g.,        rosemary extract, tea extract, magnolia extract, thymol,        menthol, eucalyptol, geraniol, carvacrol, citral, hinokitol,        catechol, methyl salicylate, epigallocatechin gallate,        epigallocatechin, gallic acid, miswak extract, sea-buckthorn        extract), bisguanide antiseptics (e.g., chlorhexidine, alexidine        or octenidine), quaternary ammonium compounds (e.g.,        cetylpyridinium chloride (CPC), benzalkonium chloride,        tetradecylpyridinium chloride (TPC),        N-tetradecyl-4-ethylpyridinium chloride (TDEPC)), phenolic        antiseptics, hexetidine, octenidine, sanguinarine, povidone        iodine, delmopinol, salifluor, metal ions (e.g., zinc salts, for        example, Zinc Chloride, Zinc Lactate, Zinc Sulfate, stannous        salts, copper salts, iron salts), sanguinarine, propolis and        oxygenating agents (e.g., hydrogen peroxide, buffered sodium        peroxyborate or peroxycarbonate), phthalic acid and its salts,        monoperthalic acid and its salts and esters, ascorbyl stearate,        oleoyl sarcosine, alkyl sulfate, dioctyl sulfosuccinate,        salicylanilide, domiphen bromide, delmopinol, octapinol and        other piperidino derivatives, nicin preparations, chlorite        salts; and mixtures of any of the foregoing.    -   1.66 Any of the preceding compositions comprising an        antioxidant, e.g., selected from the group consisting of        Co-enzyme Q10, PQQ, Vitamin C, Vitamin E, Vitamin A, BHT,        anethole-dithiothione, and mixtures thereof 1.67 Any of the        preceding compositions comprising a whitening agent.    -   1.68 Any of the preceding compositions comprising a whitening        agent selected from a whitening active selected from the group        consisting of peroxides, metal chlorites, perborates,        percarbonates, peroxyacids, hypochlorites, and combinations        thereof.    -   1.69 Any of the preceding compositions further comprising        hydrogen peroxide or a hydrogen peroxide source, e.g., urea        peroxide or a peroxide salt or complex (e.g., such as        peroxyphosphate, peroxycarbonate, perborate, peroxysilicate, or        persulphate salts; for example calcium peroxyphosphate, sodium        perborate, sodium carbonate peroxide, sodium peroxyphosphate,        and potassium persulfate), or hydrogen peroxide polymer        complexes such as hydrogen peroxide-polyvinyl pyrrolidone        polymer complexes.    -   1.70 Any of the preceding compositions, wherein the glycerin is        in an amount from 20%-40% by wt. of the composition.    -   1.71 Any of the preceding compositions, wherein the composition        further comprises sorbitol.    -   1.72 The composition of 1.72, wherein the sorbitol is from        10%-20% by wt. of the composition.    -   1.73 Any of the preceding compositions further comprising an        agent that interferes with or prevents bacterial attachment,        e.g., ethyl lauroyl arginiate (ELA) or chitosan.    -   1.74 Any of the preceding compositions comprising:        -   a. about 1.0% zinc oxide        -   b. about 0.5% zinc citrate        -   c. about 1.5% L-arginine        -   d. about 0.32% sodium fluoride;        -   e. about 35% glycerin;    -   1.75 Any of compositions 1.0-1.81 comprising:        -   a. about 1.0% zinc oxide        -   b. about 0.5% zinc citrate        -   c. about 5% L-arginine        -   d. about 0.32% sodium fluoride;        -   e. about 26% glycerin; and        -   f. about 13% sorbitol;    -   1.76 Any of the preceding compositions effective upon        application to the oral cavity, e.g., by rinsing, optionally in        conjunction with brushing, to (i) reduce or inhibit formation of        dental caries, (ii) reduce, repair or inhibit pre-carious        lesions of the enamel, e.g., as detected by quantitative        light-induced fluorescence (QLF) or electrical caries        measurement (ECM), (iii) reduce or inhibit demineralization and        promote remineralization of the teeth, (iv) reduce        hypersensitivity of the teeth, (v) reduce or inhibit        gingivitis, (vi) promote healing of sores or cuts in the        mouth, (vii) reduce levels of acid producing bacteria, (viii) to        increase relative levels of arginolytic bacteria, (ix) inhibit        microbial biofilm formation in the oral cavity, (x) raise and/or        maintain plaque pH at levels of at least pH 5.5 following sugar        challenge, (xi) reduce plaque accumulation, (xii) treat, relieve        or reduce dry mouth, (xiii) clean the teeth and oral        cavity (xiv) reduce erosion, (xv) prevents stains and/or whiten        teeth, (xvi) immunize the teeth against cariogenic bacteria;        and/or (xvii) promote systemic health, including cardiovascular        health, e.g., by reducing potential for systemic infection via        the oral tissues.    -   1.77 Any of the preceding oral compositions, wherein the oral        composition may be any of the following oral compositions        selected from the group consisting of: a toothpaste or a        dentifrice, a mouthwash or a mouth rinse, a topical oral gel,        and a denture cleanser.    -   1.78 A composition obtained or obtainable by combining the        ingredients as set forth in any of the preceding compositions.

A composition obtained or obtainable by combining the ingredients as setforth in any of the preceding compositions.

A composition for use as set for in any of the preceding compositions.

In another embodiment, the invention encompasses a method (Method 1) toimprove oral health comprising applying an effective amount of the oralcomposition of any of the embodiments set forth above to the oral cavityof a subject in need thereof, e.g., a method to

-   -   i. reduce or inhibit formation of dental caries,    -   ii. reduce, repair or inhibit early enamel lesions, e.g., as        detected by quantitative light-induced fluorescence (QLF) or        electrical caries measurement (ECM),    -   iii. reduce or inhibit demineralization and promote        remineralization of the teeth,    -   iv. reduce hypersensitivity of the teeth,    -   v. reduce or inhibit gingivitis,    -   vi. promote healing of sores or cuts in the mouth,    -   vii. reduce levels of acid producing bacteria,    -   viii. to increase relative levels of arginolytic bacteria,    -   ix. inhibit microbial bio film formation in the oral cavity,    -   x. raise and/or maintain plaque pH at levels of at least pH 5.5        following sugar challenge,    -   xi. reduce plaque accumulation,    -   xii. treat dry mouth,    -   xiii. enhance systemic health, including cardiovascular health,        e.g., by reducing potential for systemic infection via the oral        tissues,    -   xiv. Whiten teeth,    -   xv. reduce erosion of the teeth,    -   xvi. immunize (or protect) the teeth against cariogenic bacteria        and their effects, and/or    -   xvii. clean the teeth and oral cavity.

In another embodiment, the invention relates to a method to identifycandidate oral care buffering agents, compositions, solutions or systemsuseful to mitigate acidic conditions in the oral cavity. (Method 2)

Therefore, method 2 includes 2.1. A ex vivo method to identify candidateoral care buffering agents, compositions, solutions or systems useful tomitigate acidic conditions in the oral cavity comprising the steps ofproviding a first sample and a second sample, e.g., saliva, wherein thefirst and second samples have the same initial pH; contacting the firstsample with a measured quantity of acidic substance, e.g., cola, coffee,wine, orange juice or aqueous acids (i.e., 1% HCl solution) to form asolution; contacting the first sample with a candidate oral carebuffering agent, composition, solution or system; determining whetherthe pH of the first sample solution has changed; contacting the secondsample with the measured quantity of acidic substance to form asolution; contacting the second sample with any of Composition 1, etseq.; determining whether the pH of the second sample solution haschanged, wherein an increase in pH greater in the first sample beinggreater than or equal to that of the second sample indicates that thecandidate oral care buffering agents, compositions, solutions or systemscan be useful to mitigate acidic conditions in the oral cavity.

2.2 An ex vivo method to identify candidate oral care buffering agents,compositions, solutions or systems useful to mitigate acidic conditionsin the oral cavity comprising the steps of providing a first sample anda second sample, e.g., enamel from a human or bovine source; contactingthe first sample with a measured quantity of acidic substance, e.g.,cola, coffee, wine, orange juice or aqueous acids (i.e., 1% HClsolution); contacting the first sample with a candidate oral carebuffering agent, composition, solution or system; determining whetheracid erosion has occurred to the first sample; contacting the secondsample with the measured quantity of acidic substance; contacting thesecond sample with any of Composition 1, et seq.; determining whetheracid erosion has occurred to the second sample, wherein acid erosion ofthe first sample being less than or equal to that of the second sampleindicates that the candidate oral care buffering agents, compositions,solutions or systems can be useful to mitigate acidic conditions in theoral cavity.

2.3 An ex vivo method to identify candidate oral care buffering agents,compositions, solutions or systems useful to mitigate acidic conditionsin the oral cavity comprising the steps of providing a first sample anda second sample, e.g., saliva, wherein the first and second samples havethe same initial pH; contacting the first sample with a measuredquantity of a sugar, e.g., sucrose to form a solution; contacting thefirst sample with a candidate oral care buffering agent, composition,solution or system; determining whether the pH of the first samplesolution has changed; contacting the second sample with the measuredquantity of sugar to form a solution; contacting the second sample withany of Composition 1, et seq.; determining whether the pH of the secondsample solution has changed, wherein an increase in pH greater in thefirst sample that being greater than or equal to that of the secondsample indicates that the candidate oral care buffering agents,compositions, solutions or systems can be useful to mitigate acidicconditions in the oral cavity.

The invention further relates to a method to treat acid-relatedconditions in the oral cavity, comprising administering to a subject anyof Composition 1, et seq.

BRIEF DESCRIPTION OF THE FIGURES

In part, other aspects, features, benefits and advantages of theembodiments described herein will be apparent with regard to thefollowing description, appended claims and accompanying figures.

FIG. 1 illustrates the pH of whole saliva treated with zinc oxide/zinccitrate/arginine solutions before and after acid challenge with a colabeverage as a function of volume of cola added to the solution, wherethe solutions having varying concentrations of zinc oxide/zinccitrate/arginine.

FIG. 2 illustrates the pH of whole saliva treated with zinc oxide/zinccitrate/arginine solutions before and after acid challenge with a colabeverage as a function of volume of cola added to the solution incomparison with control solutions.

FIG. 3 illustrates the pH of whole saliva treated with zinc oxide/zinccitrate/arginine solutions before and after acid challenge with orangejuice as a function of volume of orange juice added to the solution,where the solutions having varying concentrations of zinc oxide/zinccitrate/arginine.

FIG. 4 illustrates the pH of whole saliva treated with zinc oxide/zinccitrate/arginine solutions before and after acid challenge with orangejuice as a function of volume of orange juice added to the solution incomparison with control solutions.

FIG. 5 illustrates the pH of whole saliva from a donor (Donor 1) treatedwith zinc oxide/zinc citrate/arginine solutions after acid challengewith a dilute hydrochloric acid as a function of reagent added to thesolution in comparison with control solutions.

FIG. 6 illustrates the pH of whole saliva from a donor (Donor 2) treatedwith zinc oxide/zinc citrate/arginine solutions after acid challengewith a dilute hydrochloric acid as a function of reagent added to thesolution in comparison with control solutions.

FIG. 7 illustrates the pH of whole saliva from a donor (Donor 3) treatedwith zinc oxide/zinc citrate/arginine solutions after acid challengewith a dilute hydrochloric acid as a function of reagent added to thesolution in comparison with control solutions.

FIG. 8 illustrates the pH of whole saliva from a donor (Donor A) treatedwith zinc oxide/zinc citrate/arginine solutions having variousconcentrations of zinc ion as a function of time.

FIG. 9 illustrates the pH of whole saliva from a donor (Donor B) treatedwith zinc oxide/zinc citrate/arginine solutions having variousconcentrations of zinc ion as a function of time.

FIG. 10 illustrates the pH of whole saliva from a donor (Donor C)treated with zinc oxide/zinc citrate/arginine solutions having variousconcentrations of zinc ion as a function of time.

FIG. 11 illustrates the pH of whole saliva from a donor (Donor A)treated with zinc oxide/zinc citrate/arginine solutions after sucrosechallenge as a function of time in comparison with control solutions.

FIG. 12 illustrates the pH of whole saliva from a donor (Donor A)treated with arginine solutions having various concentrations ofarginine after sucrose challenge as a function of time.

FIG. 13 illustrates the pH of whole saliva from a donor (Donor B)treated with arginine solutions having various concentrations ofarginine after sucrose challenge as a function of time.

FIG. 14 illustrates the pH of whole saliva from a donor (Donor C)treated with arginine solutions having various concentrations ofarginine after sucrose challenge as a function of time.

FIG. 15 illustrates the pH of whole saliva from a donor (Donor A)treated with zinc oxide/zinc citrate solutions having variousconcentrations of zinc oxide/zinc citrate after sucrose challenge as afunction of time.

FIG. 16 illustrates the pH of whole saliva from a donor (Donor B)treated with zinc oxide/zinc citrate solutions having variousconcentrations of zinc oxide/zinc citrate after sucrose challenge as afunction of time.

FIG. 17 illustrates the pH of whole saliva from a donor (Donor C)treated with zinc oxide/zinc citrate solutions having variousconcentrations of zinc oxide/zinc citrate after sucrose challenge as afunction of time.

FIG. 18 illustrates the pH of whole saliva from a donor (Donor A)treated with zinc oxide solutions having various concentrations of zincoxide after sucrose challenge as a function of time.

FIG. 19 illustrates the pH of whole saliva from a donor (Donor B)treated with zinc oxide solutions having various concentrations of zincoxide after sucrose challenge as a function of time.

FIG. 20 illustrates the pH of whole saliva from a donor (Donor C)treated with zinc oxide solutions having various concentrations of zincoxide after sucrose challenge as a function of time.

FIG. 21 illustrates the pH of whole saliva from a donor (Donor B)treated with zinc citrate solutions having various concentrations ofzinc citrate after sucrose challenge as a function of time.

FIG. 22 illustrates the pH of whole saliva from a donor (Donor B)treated with zinc citrate solutions having various concentrations ofzinc citrate after sucrose challenge as a function of time.

FIG. 23 illustrates the pH of whole saliva from a donor (Donor C)treated with zinc citrate solutions having various concentrations ofzinc citrate after sucrose challenge as a function of time.

DETAILED DESCRIPTION

As used herein, the term “oral composition” means the total compositionthat is delivered to the oral surfaces. The composition is furtherdefined as a product which, during the normal course of usage, is not,the purposes of systemic administration of particular therapeuticagents, intentionally swallowed but is rather retained in the oralcavity for a time sufficient to contact substantially all of the dentalsurfaces and/or oral tissues for the purposes of oral activity. Examplesof such compositions include, but are not limited to, toothpaste or adentifrice, a mouthwash or a mouth rinse, a topical oral gel, a denturecleanser, and the like.

As used herein, the term “dentifrice” means paste, gel, or liquidformulations unless otherwise specified. The dentifrice composition canbe in any desired form such as deep striped, surface striped,multi-layered, having the gel surrounding the paste, or any combinationthereof. Alternatively the oral composition may be dual phase dispensedfrom a separated compartment dispenser.

Basic Amino Acids

The basic amino acids which can be used in the compositions and methodsof the invention include not only naturally occurring basic amino acids,such as arginine, lysine, and histidine, but also any basic amino acidshaving a carboxyl group and an amino group in the molecule, which arewater-soluble and provide an aqueous solution with a pH of 7 or greater.

Accordingly, basic amino acids include, but are not limited to,arginine, lysine, serine, citrullene, ornithine, creatine, histidine,diaminobutanoic acid, diaminoproprionic acid, salts thereof orcombinations thereof. In a particular embodiment, the basic amino acidsare selected from arginine, citrullene, and ornithine.

In certain embodiments, the basic amino acid is arginine, for example,L-arginine, or a salt thereof.

The compositions of the invention (e.g., Composition 1.0 et seq) areintended for topical use in the mouth and so salts for use in thepresent invention should be safe for such use, in the amounts andconcentrations provided. Suitable salts include salts known in the artto be pharmaceutically acceptable salts are generally considered to bephysiologically acceptable in the amounts and concentrations provided.Physiologically acceptable salts include those derived frompharmaceutically acceptable inorganic or organic acids or bases, forexample acid addition salts formed by acids which form a physiologicalacceptable anion, e.g., hydrochloride or bromide salt, and base additionsalts formed by bases which form a physiologically acceptable cation,for example those derived from alkali metals such as potassium andsodium or alkaline earth metals such as calcium and magnesium.Physiologically acceptable salts may be obtained using standardprocedures known in the art, for example, by reacting a sufficientlybasic compound such as an amine with a suitable acid affording aphysiologically acceptable anion.

Fluoride Ion Source

The oral care compositions (e.g., Composition 1.0 et seq) may furtherinclude one or more fluoride ion sources, e.g., soluble fluoride salts.A wide variety of fluoride ion-yielding materials can be employed assources of soluble fluoride in the present compositions. Examples ofsuitable fluoride ion-yielding materials are found in U.S. Pat. No.3,535,421, to Briner et al.; U.S. Pat. No. 4,885,155, to Parran, Jr. etal. and U.S. Pat. No. 3,678,154, to Widder et al., each of which areincorporated herein by reference. Representative fluoride ion sourcesused with the present invention (e.g., Composition 1.0 et seq.) include,but are not limited to, stannous fluoride, sodium fluoride, potassiumfluoride, sodium monofluorophosphate, sodium fluorosilicate, ammoniumfluorosilicate, amine fluoride, ammonium fluoride, and combinationsthereof. In certain embodiments the fluoride ion source includesstannous fluoride, sodium fluoride, sodium monofluorophosphate as wellas mixtures thereof. Where the formulation comprises calcium salts, thefluoride salts are preferably salts wherein the fluoride is covalentlybound to another atom, e.g., as in sodium monofluorophosphate, ratherthan merely ionically bound, e.g., as in sodium fluoride.

Surfactants

The invention may in some embodiments contain anionic surfactants, e.g.,the Compositions of Composition 1.0, et seq., for example, water-solublesalts of higher fatty acid monoglyceride monosulfates, such as thesodium salt of the monosulfated monoglyceride of hydrogenated coconutoil fatty acids such as sodium N-methyl N-cocoyl taurate, sodiumcocomo-glyceride sulfate; higher alkyl sulfates, such as sodium laurylsulfate; higher alkyl-ether sulfates, e.g., of formulaCH₃(CH₂).CH₂(OCH₂CH₂).OSO₃X, wherein m is 6-16, e.g., 10, n is 1-6,e.g., 2, 3 or 4, and X is Na or, for example sodium laureth-2 sulfate(CH₃(CH₂)₁₀CH₂(OCH₂CH₂)₂OSO₃Na); higher alkyl aryl sulfonates such assodium dodecyl benzene sulfonate (sodium lauryl benzene sulfonate);higher alkyl sulfoacetates, such as sodium lauryl sulfoacetate (dodecylsodium sulfoacetate), higher fatty acid esters of 1,2 dihydroxy propanesulfonate, sulfocolaurate (N-2-ethyl laurate potassium sulfoacetamide)and sodium lauryl sarcosinate. By “higher alkyl” is meant, e.g., C₆₋₃oalkyl. In particular embodiments, the anionic surfactant (where present)is selected from sodium lauryl sulfate and sodium ether lauryl sulfate.When present, the anionic surfactant is present in an amount which iseffective, e.g., >0.001% by weight of the formulation, but not at aconcentration which would be irritating to the oral tissue, e.g., 1%,and optimal concentrations depend on the particular formulation and theparticular surfactant. In one embodiment, the anionic surfactant ispresent at from 0.03% to 5% by weight, e.g., 1.5%.

In another embodiment, cationic surfactants useful in the presentinvention can be broadly defined as derivatives of aliphatic quaternaryammonium compounds having one long alkyl chain containing 8 to 18 carbonatoms such as lauryl trimethylammonium chloride, cetyl pyridiniumchloride, cetyl trimethylammonium bromide,di-isobutylphenoxyethyldimethylbenzylammonium chloride, coconutalkyltrimethylammonium nitrite, cetyl pyridinium fluoride, and mixturesthereof. Illustrative cationic surfactants are the quaternary ammoniumfluorides described in U.S. Pat. No. 3,535,421, to Briner et al., hereinincorporated by reference. Certain cationic surfactants can also act asgermicides in the compositions.

Illustrative nonionic surfactants of Composition 1.0, et seq., that canbe used in the compositions of the invention can be broadly defined ascompounds produced by the condensation of alkylene oxide groups(hydrophilic in nature) with an organic hydrophobic compound which maybe aliphatic or alkylaromatic in nature. Examples of suitable nonionicsurfactants include, but are not limited to, the Pluronics, polyethyleneoxide condensates of alkyl phenols, products derived from thecondensation of ethylene oxide with the reaction product of propyleneoxide and ethylene diamine, ethylene oxide condensates of aliphaticalcohols, long chain tertiary amine oxides, long chain tertiaryphosphine oxides, long chain dialkyl sulfoxides and mixtures of suchmaterials. In a particular embodiment, the composition of the inventioncomprises a nonionic surfactant selected from poloxamers (e.g.,poloxamer 407), polysorbates (e.g., polysorbate 20), polyoxylhydrogenated castor oils (e.g., polyoxyl 40 hydrogenated castor oil),and mixtures thereof.

Illustrative amphoteric surfactants of Composition 1.0, et seq., thatcan be used in the compositions of the invention include betaines (suchas cocamidopropylbetaine), derivatives of aliphatic secondary andtertiary amines in which the aliphatic radical can be a straight orbranched chain and wherein one of the aliphatic substituents containsabout 8-18 carbon atoms and one contains an anionic water-solubilizinggroup (such as carboxylate, sulfonate, sulfate, phosphate orphosphonate), and mixtures of such materials.

The surfactant or mixtures of compatible surfactants can be present inthe compositions of the present invention (e.g., Composition 1.0 et seq)in 0.1% to 5%, in another embodiment 0.3% to 3% and in anotherembodiment 0.5% to 2% by weight of the total composition.

Flavoring Agents

The oral care compositions of the invention may also include a flavoringagent. Flavoring agents which are used in the practice of the presentinvention include, but are not limited to, essential oils and variousflavoring aldehydes, esters, alcohols, and similar materials, as well assweeteners such as sodium saccharin. Examples of the essential oilsinclude oils of spearmint, peppermint, wintergreen, sassafras, clove,sage, eucalyptus, marjoram, cinnamon, lemon, lime, grapefruit, andorange. Also useful are such chemicals as menthol, carvone, andanethole. Certain embodiments employ the oils of peppermint andspearmint.

The flavoring agent is incorporated in the oral composition (e.g.,Composition 1.0 et seq) at a concentration of 0.01 to 2% by weight.

Chelating and Anti-Calculus Agents

The oral care compositions of the invention also may include one or morechelating agents able to complex calcium found in the cell walls of thebacteria. Binding of this calcium weakens the bacterial cell wall andaugments bacterial lysis.

Another group of agents suitable for use as chelating or anti-calculusagents in the present invention are the soluble pyrophosphates. Thepyrophosphate salts used in the present compositions can be any of thealkali metal pyrophosphate salts. In certain embodiments, salts includetetra alkali metal pyrophosphate, dialkali metal diacid pyrophosphate,trialkali metal monoacid pyrophosphate and mixtures thereof, wherein thealkali metals are sodium or potassium. The salts are useful in boththeir hydrated and unhydrated forms. An effective amount ofpyrophosphate salt useful in the present composition is generally enoughto provide least 0.1 wt. % pyrophosphate ions, e.g., 0.1 to 3 wt 5,e.g., 0.1 to 2 wt %, e.g., 0.1 to 1 wt %, e.g., 0.2 to 0.5 wt %. Thepyrophosphates also contribute to preservation of the compositions bylowering water activity.

Polymers

The oral care compositions of the invention also optionally include oneor more polymers, such as polyethylene glycols, polyvinyl methyl ethermaleic acid copolymers, polysaccharides (e.g., cellulose derivatives,for example carboxymethyl cellulose, or polysaccharide gums, for examplexanthan gum or carrageenan gum). Acidic polymers, for examplepolyacrylate gels, may be provided in the form of their free acids orpartially or fully neutralized water soluble alkali metal (e.g.,potassium and sodium) or ammonium salts. Certain embodiments include 1:4to 4:1 copolymers of maleic anhydride or acid with another polymerizableethylenically unsaturated monomer, for example, methyl vinyl ether(methoxyethylene) having a molecular weight (M.W.) of about 30,000 toabout 1,000,000. These copolymers are available for example as GantrezAN 139 (M.W. 500,000), AN 1 19 (M.W. 250,000) and S-97 PharmaceuticalGrade (M.W. 70,000), of GAF Chemicals Corporation.

Other operative polymers include those such as the 1:1 copolymers ofmaleic anhydride with ethyl acrylate, hydroxyethyl methacrylate,N-vinyl-2-pyrollidone, or ethylene, the latter being available forexample as Monsanto EMA No. 1 103, M.W. 10,000 and EMA Grade 61, and 1:1copolymers of acrylic acid with methyl or hydroxyethyl methacrylate,methyl or ethyl acrylate, isobutyl vinyl ether or N-vinyl-2-pyrrolidone.

Suitable generally, are polymerized olefinically or ethylenicallyunsaturated carboxylic acids containing an activated carbon-to-carbonolefinic double bond and at least one carboxyl group, that is, an acidcontaining an olefinic double bond which readily functions inpolymerization because of its presence in the monomer molecule either inthe alpha-beta position with respect to a carboxyl group or as part of aterminal methylene grouping. Illustrative of such acids are acrylic,methacrylic, ethacrylic, alpha-chloroacrylic, crotonic, beta-acryloxypropionic, sorbic, alpha-chlorsorbic, cinnamic, beta-styrylacrylic,muconic, itaconic, citraconic, mesaconic, glutaconic, aconitic,alpha-phenylacrylic, 2-benzyl acrylic, 2-cyclohexylacrylic, angelic,umbellic, fumaric, maleic acids and anhydrides. Other different olefinicmonomers copolymerizable with such carboxylic monomers includevinylacetate, vinyl chloride, dimethyl maleate and the like. Copolymerscontain sufficient carboxylic salt groups for water-solubility.

A further class of polymeric agents includes a composition containinghomopolymers of substituted acrylamides and/or homopolymers ofunsaturated sulfonic acids and salts thereof, in particular wherepolymers are based on unsaturated sulfonic acids selected fromacrylamidoalkane sulfonic acids such as 2-acrylamide 2 methylpropanesulfonic acid having a molecular weight of about 1,000 to about2,000,000, described in U.S. Pat. No. 4,842,847, Jun. 27, 1989 to Zahid,incorporated herein by reference.

Another useful class of polymeric agents includes polyamino acids,particularly those containing proportions of anionic surface-activeamino acids such as aspartic acid, glutamic acid and phosphoserine, asdisclosed in U.S. Pat. No. 4,866,161 Sikes et al., incorporated hereinby reference.

In preparing oral care compositions, it is sometimes necessary to addsome thickening material to provide a desirable consistency or tostabilize or enhance the performance of the formulation. In certainembodiments, the thickening agents are carboxyvinyl polymers,carrageenan, xanthan gum, hydroxyethyl cellulose and water soluble saltsof cellulose ethers such as sodium carboxymethyl cellulose and sodiumcarboxymethyl hydroxyethyl cellulose. Natural gums such as karaya, gumarabic, and gum tragacanth can also be incorporated. Colloidal magnesiumaluminum silicate or finely divided silica can be used as component ofthe thickening composition to further improve the composition's texture.In certain embodiments, thickening agents in an amount of about 0.5% toabout 5.0% by weight of the total composition are used.

Abrasives

Natural calcium carbonate is found in rocks such as chalk, limestone,marble and travertine. It is also the principle component of egg shellsand the shells of mollusks. The natural calcium carbonate abrasive ofthe invention is typically a finely ground limestone which mayoptionally be refined or partially refined to remove impurities. For usein the present invention, the material has an average particle size ofless than 10 microns, e.g., 3-7 microns, e.g. about 5.5 microns. Forexample, a small particle silica may have an average particle size (D50)of 2.5-4.5 microns. Because natural calcium carbonate may contain a highproportion of relatively large particles of not carefully controlled,which may unacceptably increase the abrasivity, preferably no more than0.01%, preferably no more than 0.004% by weight of particles would notpass through a 325 mesh. The material has strong crystal structure, andis thus much harder and more abrasive than precipitated calciumcarbonate. The tap density for the natural calcium carbonate is forexample between 1 and 1.5 g/cc, e.g., about 1.2 for example about 1.19g/cc. There are different polymorphs of natural calcium carbonate, e.g.,calcite, aragonite and vaterite, calcite being preferred for purposes ofthis invention. An example of a commercially available product suitablefor use in the present invention includes Vicron® 25-11 FG from GMZ.

Precipitated calcium carbonate is generally made by calcining limestone,to make calcium oxide (lime), which can then be converted back tocalcium carbonate by reaction with carbon dioxide in water. Precipitatedcalcium carbonate has a different crystal structure from natural calciumcarbonate. It is generally more friable and more porous, thus havinglower abrasivity and higher water absorption. For use in the presentinvention, the particles are small, e.g., having an average particlesize of 1-5 microns, and e.g., no more than 0.1%, preferably no morethan 0.05% by weight of particles which would not pass through a 325mesh. The particles may for example have a D50 of 3-6 microns, forexample 3.8=4.9, e.g., about 4.3; a D50 of 1-4 microns, e.g. 2.2-2.6microns, e.g., about 2.4 microns, and a D10 of 1-2 microns, e.g.,1.2-1.4, e.g. about 1.3 microns. The particles have relatively highwater absorption, e.g., at least 25 g/100 g, e.g. 30-70 g/100 g.Examples of commercially available products suitable for use in thepresent invention include, for example, Carbolag® 15 Plus from LagosIndustria Quimica.

In certain embodiments the invention may comprise additionalcalcium-containing abrasives, for example calcium phosphate abrasive,e.g., tricalcium phosphate (Ca₃(PO₄)₂), hydroxyapatite(Ca₁₀(PO₄)₆(OH)₂), or dicalcium phosphate dihydrate (CaHPO₄. 2H₂O, alsosometimes referred to herein as DiCal) or calcium pyrophosphate, and/orsilica abrasives, sodium metaphosphate, potassium metaphosphate,aluminum silicate, calcined alumina, bentonite or other siliceousmaterials, or combinations thereof. Any silica suitable for oral carecompositions may be used, such as precipitated silicas or silica gels.For example synthetic amorphous silica. Silica may also be available asa thickening agent, e.g., particle silica. For example, the silica canalso be small particle silica (e.g., Sorbosil AC43 from PQ Corporation,Warrington, United Kingdom). However the additional abrasives arepreferably not present in a type or amount so as to increase the RDA ofthe dentifrice to levels which could damage sensitive teeth, e.g.,greater than 130.

Water

Water is present in the oral compositions of the invention. Water,employed in the preparation of commercial oral compositions should bedeionized and free of organic impurities. Water commonly makes up thebalance of the compositions and includes 5% to 45%, e.g., 10% to 20%,e.g., 25-35%, by weight of the oral compositions. This amount of waterincludes the free water which is added plus that amount which isintroduced with other materials such as with sorbitol or silica or anycomponents of the invention. The Karl Fischer method is a one measure ofcalculating free water.

Humectants

Within certain embodiments of the oral compositions, it is alsodesirable to incorporate a further humectant (e.g., in addition toglycerin) to reduce evaporation and also contribute towards preservationby lowering water activity. Certain humectants can also impart desirablesweetness or flavor to the compositions. The humectant, on a purehumectant basis, generally includes 15% to 70% in one embodiment or 30%to 65% in another embodiment by weight of the composition.

Suitable humectants include edible polyhydric alcohols such as glycerin,sorbitol, xylitol, propylene glycol as well as other polyols andmixtures of these humectants. Mixtures of glycerine and sorbitol may beused in certain embodiments as the humectant component of thecompositions herein (e.g., Composition 1.0 et seq).

The present invention in its method aspect involves applying to the oralcavity a safe and effective amount of the compositions described herein.

The compositions and methods according to the invention (e.g.,Composition 1.0 et seq) can be incorporated into oral compositions forthe care of the mouth and teeth such as toothpastes, transparent pastes,gels, mouth rinses, sprays and chewing gum.

As used throughout, ranges are used as shorthand for describing each andevery value that is within the range. Any value within the range can beselected as the terminus of the range. In addition, all references citedherein are hereby incorporated by reference in their entireties. In theevent of a conflict in a definition in the present disclosure and thatof a cited reference, the present disclosure controls. It is understoodthat when formulations are described, they may be described in terms oftheir ingredients, as is common in the art, notwithstanding that theseingredients may react with one another in the actual formulation as itis made, stored and used, and such products are intended to be coveredby the formulations described.

The following examples further describe and demonstrate illustrativeembodiments within the scope of the present invention. The examples aregiven solely for illustration and are not to be construed as limitationsof this invention as many variations are possible without departing fromthe spirit and scope thereof. Various modifications of the invention inaddition to those shown and described herein should be apparent to thoseskilled in the art and are intended to fall within the appended claims.

EXAMPLES

Aqueous solutions containing arginine and zinc salts were created tocarry out the following Examples. Solution 1 was prepared by mixingL-arginine (0.375 g), zinc oxide (ZnO, 0.25 g), and zinc citratetrihydrate (0.125 g) in deionized water (24.25 mL). These valuescorrespond to the following percentages by mass: 1.5% L-arginine, 1%ZnO, 0.5% zinc citrate trihydrate. Additional control solutions wereprepared of each regent alone at equal concentrations. Simple solutionpreparation is summarized in Table 1. Each solution was diluted to 25 gtotal mass with deionized water.

TABLE 1 Preparation scheme of Solutions containing Zinc Salts/Arginineand Controls Simple Solution Reagent Amount (g) Mass Percent ZincOxide/Zinc L-arginine 0.375 1.5% Citrate/Arginine ZnO 0.25 1.0% ZincCitrate 0.125 0.5% Trihydrate Arginine L-arginine 0.375 1.5% Zinc OxideZnO 0.250 1.0% Zinc Citrate Zinc Citrate 0.125 0.5% Trihydrate

Example 1—Test for Buffering Effect of Zinc Oxide/Zinc Citrate/ArginineSolution Following Acid Challenge with Cola Beverage

Paraffin-stimulated whole saliva was collected from a healthy subject.Each saliva sample was mixed by an appropriate means. Immediately priorto analysis, the ex-vivo saliva samples were pretreated with aliquots ofSolution 1 to give a range of active dilutions. A control samplecontaining untreated whole saliva was also prepared for comparison. Thedilutions were prepared as in Table 2.

TABLE 2 Concentrations of zinc oxide/zinc citrate/arginine treatedsaliva. Zinc Oxide/Zinc Whole % Zinc Oxide/Zinc Citrate/Arginine SalivaCitrate/Arginine Sample Stock (mL) (mL) Solution 1 0.00 4.000 0.000 20.100 3.900 0.025 3 0.250 3.750 0.0625 4 0.500 3.500 0.1250

The samples as described in Table 2 were tested for buffering effect onthe pH of saliva following acid challenge with a cola beverage. InitialpH values of the treated samples were obtained. A cola beverage (1 mL)was added to the saliva sample. The resultant was mixed for 30 secondsat room temperature at the conclusion of which the pH of the sample wasrecorded. This process was repeated step-wise up to a total of 40 mL ofcola. The results are shown in FIG. 1. As shown, increasingconcentrations of zinc oxide/zinc citrate/arginine alkaline shifted theisoelectric point of the saliva enhancing buffering capacity. Solutionshaving zinc oxide/zinc citrate/arginine showed strong buffering effectsat each concentration measured. However, the results show that as theconcentration of zinc oxide/zinc citrate/arginine increases, thebuffering effect on the saliva also increases.

Similar tests were carried out to compare the buffering effect againstcola of control solutions containing L-arginine/zinc oxide/zinc citrateas summarized below in Table 3.

TABLE 3 Concentrations of zinc oxide/zinc citrate/arginine treatedsaliva in comparison with controls. Whole Saliva % Reagent SampleReagent (mL) (mL) in Solution 1 Zinc Oxide/Zinc 3.750 0.0625Citrate/arginine (.250) 2 L-Arginine (.250) 3.750 0.0625 3 ZincOxide/Zinc 3.750 0.0625 Citrate (.250) 4 Zinc Oxide (.250) 3.750 0.06255 Zinc Citrate (.250) 3.750 0.0625

The titrations with the same cola beverage were repeated in presence ofsaliva treated with the aforementioned zinc oxide/zinc citrate/argininecontrols (i.e., Samples 2-5 in Table 3). The concentration of eachreagent in control Samples 2-5 were held constant in comparison to the0.0625% zinc oxide/zinc citrate/arginine simple solution. Therefore,direct comparison of any effect could be made by each control solutionto zinc oxide/zinc citrate/arginine. As shown in FIG. 2, zinc oxide/zinccitrate/arginine out performs all control solutions at equalconcentration of active agents. The zinc oxide/zinc citrate/argininesolution showed much better ability to buffer the acidic cola beveragethan the control samples. The isoelectric point of zinc oxide/zinccitrate/arginine is alkaline shifted more than 5 mL in comparison to azinc oxide/zinc citrate and a zinc oxide solution. Zinc citrate andarginine conversely acid shifted the isoelectric point in comparison tothe untreated sample providing no acid neutralization benefit.

Example 2—Test for Buffering Effect of Zinc Oxide/Zinc Citrate/ArginineSolution Following Acid Challenge with Orange Juice

Four solutions containing whole saliva and zinc oxide/zinccitrate/arginine at varying proportions were prepared in accordance withthe methods laid out in Example 1 above. The solutions contained thesame concentrations as Samples 1-4 as defined in Table 2. The sampleswere tested for buffering effect on the pH of saliva following acidchallenge with orange juice. Initial pH values of the treated sampleswere obtained. Orange juice (0.1 mL) was added to the saliva sample. Theresultant was mixed for 30 seconds at room temperature at the conclusionof which the pH of the sample was recorded. This process was repeatedstep-wise up to a total of 3.0 mL of orange juice. After this point,orange juice was added to the samples in an amount of 0.5 mL up to 5.0mL. The results are shown in FIG. 3. As shown, increasing concentrationsof zinc oxide/zinc citrate/arginine alkaline shifted the isoelectricpoint of the saliva enhancing buffering capacity. Zinc oxide/zinccitrate/arginine solutions showed strong buffering effects at eachconcentration measured. However, the results show that as theconcentration of zinc oxide/zinc citrate/arginine increases, thebuffering effect on the saliva also increases, especially at moderateamounts of orange juice (i.e., between 2 and 3 mL).

Similar tests as those in Example 1 were carried out to compare thebuffering effect against orange juice of solutions containingL-arginine/zinc oxide/zinc citrate with control solutions as summarizedabove in Table 3. The titrations with the same orange juice wererepeated in presence of saliva treated with controls (i.e., Samples 2-5in Table 3). The concentration of each reagent in control Samples 2-5were held constant in comparison to the 0.0625% zinc oxide/zinccitrate/arginine simple solution. As shown in FIG. 4, the zincoxide/zinc citrate/arginine solution showed an ability to buffer theacidic orange juice beverage better than or on par with the controlsamples. The isoelectric point of zinc oxide/zinc citrate/arginine iscomparable to that of the zinc oxide/zinc citrate and zinc oxidesolution. Zinc citrate alone showed no benefit in comparison theuntreated control.

Taken together, the data clearly demonstrate the role of zinc oxide/zinccitrate/arginine in enhancing the resistance of saliva to acidicbeverages. The data suggest the complex of L-arginine/zinc oxide/zinccitrate, not the entities thereof (arginine, zinc), are required forbuffering effect.

Example 3—Test for Buffering Effect of Zinc Oxide/Zinc Citrate/ArginineSolution Following Acid Challenge with Hydrochloric Acid

Paraffin-stimulated whole saliva was collected from three healthysubjects (Donors 1-3). Each saliva sample was mixed by ordinary means inthe art. Immediately prior to analysis, the ex-vivo saliva samples werepretreated with aliquots of the simple solutions to give a range ofactive dilutions (i.e., total Zn²⁺ concentration of about 0-1500 ppm)including an untreated control. The concentrations of actives (i.e.,zinc oxide/zinc citrate/arginine, L-arginine, zinc oxide, zinc citrate)were varied between 0.0% to 50% across all samples, as shown in FIGS.5-10.

An initial pH of the treated sample was obtained. Dilute hydrochloricacid (HCl, 0.01 M, 6 mL) was added to each saliva sample. The resultantwas mixed for 20 minutes at room temperature. The pH of the sample wasrecorded at the conclusion of the reaction time. Zinc concentration ineach sample was determined by ICP-AES. The results are summarized inFIGS. 5-10.

FIGS. 5-7 show the superior acid buffering effects of even small amountsof zinc oxide/zinc citrate/arginine over subsequent control solutions.the results indicate that the combination of zinc and L-arginine booststhe acid buffering capacity of saliva over the L-arginine control.Surprisingly, this augmentation (up to 2 pH log units) is most evidentin individuals with low salivary buffering capacity (Donor #1 and Donor#3) at very low amounts of treatment (<0.200 For example, FIGS. 5-7 eachshow that the samples having 200 μL or less zinc oxide/zinccitrate/arginine showed much better buffering of the acid solutions thaneach of the arginine, zinc oxide or zinc citrate solutions at the sameconcentrations. The same figures show that only solutions containingvery high amounts of L-arginine (>500 μL) were able to match thiseffect. Zinc oxide provided some pH stabilization in treated samplesupon acid exposure. However, this effect was quickly exhausted, notshowing a dose response above 0.1% treatment. Furthermore, the overallpH of the saliva after acid exposure was lower in saliva treated withZnO than zinc oxide/zinc citrate/arginine treated saliva. This leads toa larger change in pH upon acid exposure in ZnO samples, decreasingbenefits on this active in comparison to zinc oxide/zinccitrate/arginine. In all donors, zinc citrate provided little to nobuffering effect at all, dropping the pH of all treated samples below4.0.

Example 4—Test for Buffering Effect of Zinc Oxide/Zinc Citrate/ArginineSolution Following Sucrose Challenge

Paraffin-stimulated whole saliva was collected from three healthysubjects (Donors A-C). Each saliva sample was mixed by ordinary means inthe art. Prior to analysis, the ex-vivo saliva samples were pretreatedwith aliquots of the simple solutions to give a range of activedilutions (i.e., total Zn²⁺ concentration of about 0-3000 ppm) includingan untreated control in order to test for buffering effect againstsucrose challenge as a function of zinc concentration. An initial pH ofthe treated sample was obtained. A sucrose solution (5%, 1 mL) was addedto each saliva sample. The resultant was mixed for and then incubated at37° C. and the pH was monitored at 2 hours, 4 hours, 6 hours, andovernight. Zinc concentration in each sample was determined by ICP-AES.

Charts showing the pH of the saliva of each donor pre- and post-sucrosechallenge as a function of zinc (i.e., in zinc oxide/zinccitrate/arginine solutions) concentration and time are shown in FIGS.8-10. The control sample of each donor saliva shows a steady drop as afunction of time consistent with unregulated acid production by oralbacteria. However, upon adding zinc oxide/zinc citrate/arginine, theeffect on pH dropping is greatly attenuated, even at smallerconcentrations of zinc.

With specific reference to FIG. 8, solutions containing concentrationsof at least about 580 ppm Zn²⁺ showed a stable buffering effect acrossthe entire testing period. FIG. 10 shows similar results for solutionscontaining concentrations of at least about 478 ppm Zn²⁺. FIG. 9 showsthat concentrations above 600 ppm Zn²⁺ (i.e., 1400 and 3000 ppm) exhibitstable saliva buffering across the entire testing period, while thesolution containing 600 ppm Zn²⁺ showed a slight drop in bufferingeffect after 6 hours. This buffering effect increases as theconcentration of zinc ions increase in the composition.

Further experiments were conducted to ensure that zinc oxide/zinccitrate/arginine, not its constituent parts, was needed to achieve thebuffering capacity improvement described. The solutions tested wereprepared according to the specifications as laid out in Table 3 above.As seen by FIG. 11, zinc oxide/zinc citrate/arginine out performs itsconstituent controls in maintaining a stable pH in response to bacterialacid production.

As shown in FIGS. 12-14, pH of the saliva from donors A-C were tested insucrose challenged conditions as a function of arginine concentration.It is only at relatively high concentrations of arginine that anyappreciable buffering effect is observed (i.e., 250 ppm to 500 ppmarginine). In donor C, modest buffering was observed with the 100 ppmarginine solution, but this effect was not seen in donors A or B.

As shown in FIGS. 15-17, pH of the saliva from donors A-C were tested insucrose challenged conditions as a function of zinc oxide/zinc citrateconcentration. Buffering effects were clearly observed over theuntreated control of donor B as shown in FIG. 16, but none of the zincoxide/zinc citrate solutions in FIGS. 15-17 show a similar high level ofbuffering effect as the zinc oxide/zinc citrate/arginine solution.

As shown in FIGS. 18-20, pH of the saliva from donors A-C were tested insucrose challenged conditions as a function of zinc oxide concentration.Buffering effects were clearly observed over the untreated control ofeach of the donors, but none of the zinc oxide/zinc citrate solutions inFIGS. 18-20 show a similar high level of buffering effect as the zincoxide/zinc citrate/arginine solution.

As shown in FIGS. 21-23, pH of the saliva from donors A-C were tested insucrose challenged conditions as a function of zinc citrateconcentration. Buffering effects were observed over the untreatedcontrol of each of the donors, but none of the zinc oxide/zinc citratesolutions in FIGS. 21-23 show a similar high level of buffering effectas the zinc oxide/zinc citrate/arginine solution.

Based on the above, it is apparent that zinc oxide/zinc citrate/arginineis has an effect on saliva buffering capacity. Without being bound bytheory, the results indicate that zinc oxide/zinc citrate/arginine canprevent the activities or neutralize the products of acid-causingbacteria. Additionally, the effect on pH could attributed to theantibacterial effects of zinc oxide/zinc citrate/arginine.

Example 5—Representative Formulation

In one representative formulation, a dentifrice comprises the following:

-   -   a. 1.0 wt. % zinc oxide    -   b. 0.5 wt. % zinc citrate    -   c. 1.5 wt. % L-arginine    -   d. 0.32 wt. % sodium fluoride; and    -   e. 35% wt. glycerin

Example 6—Representative Dentifrice Formulation

Representative Dentifrice Formulation:

Ingredient Formula 1 DEMINERALIZED WATER Q.S. ABRASIVES 10%-20%99.0%-101.0% GLYCERIN - USP, EP VEG 35   L-Arginine 1.5 AMPHOTERICSURFACTANT 1.0%-1.5% NON-IONIC SURFACTANT 0.25%-0.75% POLYMERS0.75%-1.5%  ALKALI PHOSPHATE SALT 0.25%-0.75% ZINC CITRATE TRIHYDRATE0.5 WHITENING AGENT 0.25%-1.0%  FLAVORING AGENTS 1.5%-1.9% 85% SYRUPYPHOSPHORIC ACID - FOOD GRADE   0-0.35 SODIUM FLUORIDE - USP, EP  0.32SILICA - THICKENER 5%-7% ANIONIC SURFACTANT 1%-3% ZINC OXIDE 1  PRESERVATIVE 0.4 Total Components 100

While the present invention has been described with reference toembodiments, it will be understood by those skilled in the art thatvarious modifications and variations may be made therein withoutdeparting from the scope of the present invention as defined by theappended claims.

1. An oral care buffering composition comprising: a) a basic amino acidin free or salt form wherein the amino acid is arginine; b) zinc oxideand zinc citrate; and c) an orally acceptable carrier, wherein the oralcare composition provides a buffering effect against acidic conditionsin the oral cavity following acid challenge or sucrose challenge,wherein the buffering effect is greater than a corresponding bufferingeffect of compositions comprising arginine, zinc oxide or zinc citratealone.
 2. The oral care composition of claim 1, wherein the compositionmaintains a pH over 5.0 when challenged in an acidic aqueous solutionwith a cola beverage in an amount of about 90% v/v based on the totalvolume of the solution.
 3. The oral care composition of claim 1, whereinthe composition maintains a pH over 3.9 when challenged in an acidicaqueous solution with a cola beverage in an amount of about 90% v/vbased on the total volume of the solution.
 4. The oral care compositionof claim 1, wherein the composition maintains a pH over 3.0 whenchallenged in an acidic aqueous solution with a cola beverage in anamount of about 90% v/v based on the total volume of the solution. 5.The oral care composition of claim 1, wherein the composition maintainsa pH over 5.5 when challenged in an acidic aqueous solution with a colabeverage in an amount of about 80% v/v based on the total volume of thesolution.
 6. The oral care composition of claim 1, wherein thecomposition maintains a pH over 4.0 when challenged in an acidic aqueoussolution with orange juice in an amount of about 55% v/v based on thetotal volume of the solution.
 7. The oral care composition of claim 1,wherein the composition maintains a pH over 6.0 when challenged in anacidic aqueous solution with orange juice in an amount of about 33% v/vbased on the total volume of the solution.
 8. The oral care compositionof claim 1, wherein the composition maintains a pH over 5.0 whenchallenged in an acidic aqueous solution with orange juice in an amountof about 33% v/v based on the total volume of the solution.
 9. The oralcare composition of claim 1, wherein the composition maintains a pH over7.0 when challenged in an acidic aqueous solution with 0.01M aqueous HClin an amount of about 60% v/v based on the total volume of the solution.10. The oral care composition of claim 1, wherein the compositionmaintains a pH over 8.0 when challenged in an acidic aqueous solutionwith 0.01M aqueous HCl in an amount of about 60% v/v based on the totalvolume of the solution.
 11. The oral care composition of claim 1,wherein the composition maintains a pH over 7.0 6 hours after sucrosechallenge.
 12. The oral care composition of claim 1, wherein thecomposition maintains a pH over 8.0 6 hours after sucrose challenge. 13.The oral care composition of claim 1, wherein the composition maintainsa pH over 9.0 6 hours after sucrose challenge.
 14. The oral carecomposition of claim 1, wherein the composition maintains a pH over 7.024 hours after sucrose challenge.
 15. The oral care composition of claim1, wherein the composition maintains a pH over 8.0 24 hours aftersucrose challenge.
 16. The oral care composition of claim 1, wherein thecomposition maintains a pH over 9.0 24 hours after sucrose challenge.17. The oral care composition of claim 1, wherein the arginine has theL-configuration.
 18. The oral care composition of claim 1 wherein theamino acid is arginine from about 1.5 wt. %.
 19. The oral carecomposition of claim 1, wherein the zinc citrate is in an amount ofabout 0.5 wt % and zinc is present in an amount of about 1.0% based onthe weight of the oral care composition.
 20. A method to identifycandidate oral care buffering agents, compositions, solutions or systemsuseful to mitigate acidic conditions in the oral cavity comprising thesteps of providing a first sample and a second sample selected fromenamel from a human or bovine source; contacting the first sample with ameasured quantity of acidic substance; contacting the first sample witha candidate oral care buffering agent, composition, solution or system;determining whether acid erosion has occurred to the first sample;contacting the second sample with the measured quantity of acidicsubstance; contacting the second sample with the oral care compositionof claim 1; determining whether acid erosion has occurred to the secondsample, wherein acid erosion of the first sample being less than orequal to that of the second sample indicates that the candidate oralcare buffering agents, compositions, solutions or systems can be usefulto mitigate acidic conditions in the oral cavity.
 21. A method toidentify candidate oral care buffering agents, compositions, solutionsor systems useful to mitigate acidic conditions in the oral cavitycomprising the steps of providing a first sample and a second sampleselected from enamel from a human or bovine source; contacting the firstsample with a measured quantity of acidic substance; contacting thefirst sample with a candidate oral care buffering agent, composition,solution or system; determining whether acid erosion has occurred to thefirst sample; contacting the second sample with the measured quantity ofacidic substance; contacting the second sample with the oral carecomposition of claim 1; determining whether acid erosion has occurred tothe second sample, wherein acid erosion of the first sample being lessthan or equal to that of the second sample indicates that the candidateoral care buffering agents, compositions, solutions or systems can beuseful to mitigate acidic conditions in the oral cavity.
 22. A method toidentify candidate oral care buffering agents, compositions, solutionsor systems useful to mitigate acidic conditions in the oral cavitycomprising the steps of providing a first sample and a second sampleselected from saliva, wherein the first and second samples have the sameinitial pH; contacting the first sample with a measured quantity of asugar to form a solution; contacting the first sample with a candidateoral care buffering agent, composition, solution or system; determiningwhether the pH of the first sample solution has changed; contacting thesecond sample with the measured quantity of sugar to form a solution;contacting the second sample with the oral care composition of claim 1;determining whether the pH of the second sample solution has changed,wherein an increase in pH greater in the first sample that being greaterthan or equal to that of the second sample indicates that the candidateoral care buffering agents, compositions, solutions or systems can beuseful to mitigate acidic conditions in the oral cavity.